Induction of Apoptosis of 2,4′,6-Trihydroxybenzophenone in HT-29 Colon Carcinoma Cell Line

1Institute of Biological Sciences, Faculty of Science, University of Malaya, 50603 Kuala Lumpur, Malaysia2University of Malaya Centre for Proteomics Research (UMCPR), University of Malaya, 50603 Kuala Lumpur, Malaysia

Received 24 August 2013; Accepted 22 October 2013; Published 22 January 2014

Abstract

2,4′,6-Trihydroxy-4-methoxybenzophenone was isolated from the ethyl acetate fraction of Phaleria macrocarpa (Scheff.) Boerl. fruits. It was found to inhibit cell proliferation in HT-29 human colon carcinoma cell line but caused little damage to WRL-68 normal human liver and MRC-5 normal human fibroblast lung cell lines. The compound was found to sharply affect the viability of HT-29 cells in a dose- and time-dependent manner. HT-29 cells treated with the compound showed morphological changes under microscopic examination such as cell shrinkage, membrane blebbing, DNA fragmentation, and the occurrence of apoptotic nuclei. The percentage of early apoptotic, late apoptotic, and dead or necrotic cells was determined by flow cytometry using annexin V-FTIC/PI staining. In addition, flow cytometry showed that, when the HT-29 cells were treated with 115 µM of the compound, it resulted in G0/G1 phase arrest in a time-dependent manner. Western blot revealed an upregulation of PUMA, Bak, Bcl-2, and Mcl-1 proteins suggesting that the compound induced apoptosis in HT-29 cells by regulating these proteins.